(a) Field of the Invention
The present invention relates to a method and apparatus for protection switching. More particularly, the present invention relates to a method and apparatus for protection switching in a packet transport system.
(b) Description of the Related Art
Due to popularization of the Internet and integration of wired and wireless Internet, data traffic has increased, and a limitation exists in housing a high quality service such as IP-TV with an existing complicated network. Accordingly, methods of a transmitting service that provides extension and end-to-end quality of service (QoS) using a data link layer such as a multi-protocol label switching-transport profile (MPLS-TP) of an Internet Engineering Task Force (IETF), IEEE 802.1ah (provider backbone bridging (PBB), and IEEE 802.1ag (provider backbone bridging-traffic engineering (PBB-TE) are being studied.
In order for a packet transport network to provide a non-stop service to users by stably operating and to maximize efficiency of a network, a method of processing failure occurrence or performance deterioration is necessary. Such a method includes a method of protection switching and restoration.
Protection switching is a method of resuming traffic as soon as possible when traffic is stopped, when a failure occurs in a network. Protection switching is classified into linear protection switching and ring protection switching according to topology of a network, and the linear protection switching is classified into 1+1, 1-to-1, 1-to-N, or M-to-N protection switching.
Protection switching basically divides paths between nodes into a working path and a protection path, and when a failure does not exist, traffic is carried with the working path, and when a failure occurs in a network or when a path is changed according to operator control, traffic is carried through the protection path.
A restoration method restores a stopped service to an original service using an available path and resource in a network after a failure occurs.
Protection switching in such a packet transport system is performed using an automatic protection switching (APS) frame and an operation, administration, and maintenance (OAM) frame including protection switching protocol message information between a packet processor, a host processor, and a main processor that are mounted within a line card of the packet transport system.
However, by processing protection switching in software having a relatively lower speed based on a processor, a continuity check and connectivity verification requiring real-time processing is not efficiently performed, and when a packet is lost according to a specific failure situation, performance of a packet transport system may be deteriorated.